Qik 2s10v10 vs TReX DMC01

Basically my question is: What is the difference between these two controllers?

I’m looking to purchase a high-amp dual motor controller (exact motors have not been selected yet). The two best options seem to be the ‘Qik 2s12v10 Dual Serial Motor Controller’ and ‘TReX Dual Motor Controller DMC01’. In the product comparison table, the only differences I can see are that the TReX is capable of RC servo pulses and analog voltage, where the Qik is not. Otherwise, all the current/voltage/frequency specs are identical.

I’ve been comparing the two user guides and the protocols look nearly identical as well. The only two major differences I see are:

[ol][li]The TReX has a single command option for simultaneously setting M0 & M1, where the Qik needs two independent commands, one for each motor.
[/li]
[li]The TReX has commands to accelerate and set the motor speeds, where the Qik can only set the motor speed, but has an acceleration parameter.[/li][/ol]

Based on these differences though, it doesn’t seem to warrant the $25 price difference, so I’m guessing there’s some feature(s) that I’m just missing. Thanks in advance for any advice/feedback!

Hello.

The basic differences between those motor controllers can be seen in the comparison chart on the “Brushed DC Motor Controllers” page. As you mentioned, the TReX accepts serial, analog, or RC inputs, while the Qik is limited to just serial. The TReX also has an additional auxiliary motor channel.

You might consider looking at the Simple Motor Controllers (SMC) as well. While the SMCs are not dual motor controllers, they have many useful features and the USB control and software make them easy to use. I would generally recommend using two SMCs over either the TReX or the Qik.

-Brandon

Thanks for your reply. I’m reviewing the user guide for the simple motor controller, and do agree, there are some significant advantages with the USB control and software. I think you have me sold.

I have a question about daisy chaining. Is it possible to send a broadcast command so that each controller simultaneously acts? For example, driving the robot forward since both would get the same command and speed. And if not, have you ever noticed any lag/delay when controlling 2 drive motors?

Oh, one final question on selection. I’ll be using 2 30:1 37D mm gearmotors motors @ 12v. Which SMC would you recommend? Per the specs, the 18v7 should be sufficient since it has a max continuous current rating of 7A and the motor’s stall current @ 12V is 5A. However, I have burned out a TReX Jr DMC02 in the past using it under the rated current limits. I would just go up to the 18v15, but we are under pretty tight budget constraints, so ever $ counts.

You can send a single command to all SMCs in a daisy chain like you described by using the Compact Protocol. Since the Compact Protocol does not specify a device number, all SMCs will respond to it. Please note that you can switch between sending Compact Protocol and Pololu Protocol commands on-the-fly (e.g. you do not need to configure the SMC for each protocol). The delay from sending two serial commands (one for each SMC) is very minimal and probably negligible in most applications.

As for choosing an appropriate version of the controller, we generally recommend choosing a controller that has a continuous current rating that is greater than or equal to the stall current of your motors. In this case, the 18v7 has a continuous current rating of 7A and a peak current of 30A (much higher than the TReX Jr.), so it should be appropriate for driving one of our 37D motors at 12V.

-Brandon